Fluffy BL

don't know a lot of "fluff" but I find these and most from webtoon to be very sweet :)
Novae
Castle Swimmer
The Reaper and the Waiting

https://www.mangago.zone/read-manga/hana_tokidoki_kuma/

Sign / cherry blossoms after winter

https://www.mangago.zone/read-manga/boys_love_jagal/

https://www.mangago.zone/read-manga/sora_haena/

https://www.mangago.zone/read-manga/cool_doji_danshi/

https://www.mangago.zone/read-manga/faded_first_love/

https://www.mangago.zone/read-manga/we_re_still_in_the_spring_of_life/
https://www.mangago.zone/read-manga/chang_le_makes_me_unable_to_confess/

https://www.mangago.zone/read-manga/the_story_about_you_x_me/

https://www.mangago.zone/read-manga/kawa_ni_sazanami/

https://www.mangago.zone/read-manga/mr_villain_s_day_off/

https://www.mangago.zone/read-manga/megane_tokidoki_yankee_kun/

https://www.mangago.zone/read-manga/young_lad_s_wool_shop/

https://www.mangago.zone/read-manga/rutta_to_kodama/
https://www.mangago.zone/read-manga/yamada_to_shounen/
https://www.mangago.zone/read-manga/kowagaranai_de_soba_ni_ite/
https://www.mangago.zone/read-manga/renai_chuudoku_mikage_tsubaki/ - no really fluff, but it was cute